1. Field of the Invention
The present invention relates to a photoelectric conversion element and a method of manufacturing the photoelectric conversion element.
2. Description of the Related Art
A pixel array portion of a photoelectric conversion element, in which photodiodes are arranged, includes regions which light enters and light-shielded regions. Each light-shielded region is also called an optical black region (OB), which is used as a region for generating a signal as a reference for an image sensor. Some light-shielded regions have unevenness formed on their surfaces. Japanese Patent Laid-Open No. 2012-204402 discloses a technique of forming an uneven surface by etching a region above a light-shielded region simultaneously with the etching of the surface of an image sensor for the formation of openings in pad portions for interconnection. According to Japanese Patent Laid-Open No. 2012-204402, since the surface of a light-shielded region is made of the same material as that for a microlens, it has been impossible to find etching conditions suitable for the formation of unevenness on the surface by etching. In order to form unevenness on the surface by etching, the number of steps increases, including preparing a resist mask on a microlens portion, resulting in the prolongation of the etching process.